Locking stacking lug for stackable containers

ABSTRACT

A stackable container ( 10 ) has a generally cylindrical body with a rounded top ( 12 ), a rounded bottom ( 14 ), and a sidewall ( 16 ). A pair of opposed ears ( 26 ) formed below the top of the body extend outwardly from the side of the body for attaching ends of a handle ( 24 ) used to lift and carry the container. The container has a locking mechanism for stacking the container with a similarly formed container so the containers are securely attached to each other to facilitate their movement. The container has a circumferential lip ( 18 ) formed about the top of the container and a pair of opposed notches ( 30 ) are formed in the lip. A pair of lugs ( 32 ) extend outwardly from the container sidewall and are sized to fit into the notch when two containers are stacked together so to attach the containers to each other and facilitate stacking of the containers. In one embodiment the notches and lugs are aligned with the respective ears; while in another embodiment they are offset from the ears.

BACKGROUND OF THE INVENTION

This invention relates to stackable containers such as plastic pails and the like; and more particularly, to containers having locking stacking lugs which allow nested containers to be stacked more uniformly.

Containers such as plastic pails are designed so that containers of the same size and shape can be fitted within one another, or nested. The resulting stack of containers can include a large number of containers. Typically, as more containers are stacked together, the stack becomes unwieldy and may topple over. To prevent this, molded plastic containers are often formed so that they can be stacked together only in a certain way. By requiring a container to be placed inside another container in a preferred orientation, the stack is made more stable and less prone to toppling or falling over. Examples of such prior art container constructions are shown, for example, FIGS. 1 and 2 of the accompanying drawings.

Even though containers may be designed to nest in a preferred way does not guarantee that they actually will be. Rather, many prior art containers can still be stacked so that they do not properly align with each other, thereby defeating the purpose of their construction. This is also important because stacked pails are often placed on pallets for storage, or for movement from one location to another. A typically pallet may contain sixteen (16) stacks of twenty (20) containers each. For ease of palletizing the containers, it is helpful if the containers are stacked uniformly. If they are not, then someone will have to manually align the containers before they are placed on the pallet. Also, many times, when the containers are subsequently removed from the pallet, a machine is used to automatically remove or “de-nest” them. If the containers are not properly aligned in a stack, this causes stoppage of the machine and requires further manual labor to complete removal of the containers.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a molded plastic container having opposed locking grooves formed at predetermined locations on the outside edge of the top lip of the pail. Opposed locking lugs which fit in the grooves are formed beneath a ring extending circumferentially about a pail and spaced a desired distance beneath the top of the pail. In one embodiment, the grooves and the corresponding lugs are aligned with ears formed on the sides of the container to receive ends of a bail or handle used to lift and carry the container. In another embodiment, the groves and lugs are offset from the lugs.

When the pails are stacked, the locking lugs are received in the grooves to lock the pails together. The lugs and their associated grooves now prevent the pails from shifting with respect to each other. They also allow containers to be easily stacked in a proper alignment facilitating efficiencies in both the palletizing and de-palletizing of the containers.

Other objects and features will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The objects of the invention are achieved as set forth in the illustrative embodiments shown in the drawings which form a part of the specification.

FIGS. 1 and 2 are representative examples of prior art stackable container constructions;

FIG. 3 is a side elevation of stackable containers made in accordance with the present invention;

FIG. 4 is a perspective view of the container illustrating the locking lug and groove;

FIG. 5 is a side elevation of a two stacked or nested containers of the present invention;

FIG. 6 is a perspective view illustrating two stacked or nested containers;

FIGS. 7A and 7B are respective plan and elevation views of palletized containers;

FIGS. 8 and 9 are views respectively similar to those in FIGS. 4 and 6 for a second embodiment of the invention in which the locking lug and groove are aligned with an ear formed on the side of a container for receiving an end of a handle used to lift and carry the container; and,

FIGS. 10 and 11 are views respectively similar to those in FIGS. 8 and 9 for a third embodiment of the invention only an upper circumferential flange extends around the side of the container.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF INVENTION

The following detailed description illustrates the invention by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what I presently believe is the best mode of carrying out the invention. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Referring to the drawings, FIGS. 7A and 7B illustrate a pallet P on which is arranged stacks of containers C. In a typical pallet arrangement, stacks of containers are arranged in four (4) rows and four (4) columns when viewed from above in FIG. 7A. As shown in FIG. 4, each stack in this 4×4 arrangement includes up to twenty containers C1-C20 vertically stacked or nested together. As noted previously, in order to conveniently stack, store, and move the palletized containers, the containers should nest together so that they can be readily stacked and unstacked using automated equipment.

In FIGS. 1 and 2, examples of prior art containers are shown. In FIG. 1, containers C′ are nested together. Each container has a notch N′ formed in its upper rim R′ immediately above an ear E′ which extends outwardly from the side of the container. One end of a bail or handle H′ is rotatably attached to the ear. As the upper container C′ is lowered into the lower container a portion of the ear in the upper container is supposed to fit into the notch in the lower container to nest the containers together so they can be readily handled.

In FIG. 2, a container C″ has a notch N″ formed in its upper rim R″ immediately above an ear E″ which extends outwardly from the side of the container. A handle H″ has one end rotatably attached to the ear. When the upper container C″ is lowered into the lower container, a portion of ear E″ in the upper container is supposed to fall into notch N″ in the lower container. The resulting stack of containers is again supposed to be readily handled.

As shown in FIGS. 3 and 4, a container 10 of the present invention is a molded plastic container or pail. The container may be of different sizes and may or may not have a lid, depending upon the type of material stored or carried in the pail. The pail is generally cylindrical in form, having a rounded top 12 and a rounded base 14, and a sidewall 16 which tapers from the top to the bottom of the container. A circumferential lip or rim 18 extends around the top of the pail. A pair of annular flanges 20, 22 extend outwardly of sidewall 16, and around the pail, a distance below the top of the container. Flange 20 comprises an upper flange and flange 22 a lower flange in this regard. The pail includes a removable bail or handle 24 for lifting and carrying the container, and respective ears or tabs 26 (only one of which is shown in the drawings) are formed opposite sides of the container and project outwardly from the side of the container. The ears or tabs extend vertically between the upper and lower flanges, and each tab includes an opening 28 for receiving and securing an end of handle 24.

A locking means for attaching container 10 to a similarly formed container with which it is stacked first includes a pair of notches or grooves 30 are formed on the outer margin of lip 18 of container 10 on opposite sides of the container. A mating pair of lugs 32 is formed on lower flange 22 of the container on opposite sides of the container. Again, only one of the notches and one of the lugs are shown in the drawings. In this embodiment, the notches are not formed over the location of the ears 26, but rather are offset to one side of the ears. The lugs 32, which depend beneath lower flange 22 are correspondingly offset from the location of the ears, but the lugs and notches are vertically aligned with each other.

In FIGS. 5 and 6, two containers 10-1 and 10-2 are shown vertically stacked or nested together. As shown in the drawings, as container 10-1 is lowered into container 10-2, whether by hand or by automated equipment, one or both of the containers are rotated until the tabs 32 on container 10-1 are aligned with the notches 30 on container 10-2. With the tabs on container 10-1 fitted in the notches on container 10-2, the two containers are effectively “locked” together.

Locking the containers together has a number of significant advantages. First, it allows the pails to be stacked together in a more uniform and controlled manner. Next, it improves handling of container stacks, regardless of the number of containers in a stack. It also makes it easier for automatic nesting and de-nesting equipment to handle the containers. In this regard, by offsetting the notches 30 and lugs 32 from the location where the ends of a handle attach to a container, it removes a possible obstruction with the handle, if it is attached to the container. Further, out of line ears on pails causes stoppages of de-nesting equipment, increasing handling costs of the containers.

Since containers are often palletized for transport from storage to assembly or shipping sites, the present invention both makes it easier to stack a large number of containers, but to then also transport and unload them. This is accomplished using the automatic alignment feature of the present invention.

Referring to FIGS. 8 and 9, a second embodiment of the invention includes a container 100 having a circumferential rim 118 extends around the top of the pail. Container 100 has a pair of annular flanges 120, 122 extending outwardly of a container sidewall 116, a distance below the top of the container. Flange 120 comprises an upper flange on the container, and flange 122 a lower flange. Again the pail has a removable bail handle used for lifting and carrying the container. Respective ears 126 (only one of which is shown in the drawings) are formed opposite sides of the container, project outwardly from the side of the container, and extend vertically between the upper and lower flanges. Each tab 126 includes an opening 28 for receiving and securing an end of the handle.

A locking means for stacking containers 100 includes a pair of notches 130 formed on the outer margin of lip 118 on opposite sides of the container. A mating pair of locking lugs 132 is formed on lower flange 122 of the container, on opposite sides of the container. In this embodiment, the notches 130 are formed directly above the respective ears 126, and the lugs 132 now depend beneath lower flange 122 directly below the ears. The notches and lugs are vertically aligned with each other.

In FIG. 9, two containers 100-1 and 100-2 are shown vertically stacked or nested together. As with the previous embodiment, container 100-1 is lowered into container 100-2, by hand or using automated equipment. Again, the containers are rotated until the tabs 132 on container 100-1 align with the notches 130 on container 100-2. When the tabs on container 100-1 are now fitted in the notches on container 100-2, the containers are locked together.

Referring to FIGS. 10 and 11, a third embodiment of the invention comprises a container 200 having a circumferential rim 218 extends around the top of the pail and an annular flange 220 extending outwardly of a container sidewall 216, a distance below the top of the container. Again the pail has a removable bail handle used for lifting and carrying the container. Respective ears 226 (only one of which is shown in the drawings) are formed opposite sides of the container, project outwardly from the side of the container, and depend beneath flange 220. Each tab 226 includes an opening 228 for receiving and securing an end of the handle.

A locking means for stacking containers 200 includes a pair of notches 230 formed on the outer margin of lip 218 on opposite sides of the container. A mating pair of locking lugs 232 extends below the respective ears 226 on opposite sides of the container. In this embodiment, the notches 230 are again formed directly above the respective ears 226 so they are vertically aligned.

In FIG. 11, two containers 200-1 and 200-2 are shown vertically stacked or nested together. As with the previous embodiments, container 200-1 is lowered into container 200-2, by hand or with automated equipment. Again, the containers are rotated until the tabs 232 on container 200-1 align with the notches 230 on container 200-2. When the tabs on container 200-1 are now fitted in the notches on container 200-2, the containers are locked together.

In view of the above, it will be seen that the several objects and advantages of the present invention have been achieved and other advantageous results have been obtained. 

1. A stackable container comprising: a generally cylindrical body with a rounded top, a rounded bottom, and a sidewall; a pair of opposed ears formed below the top of the body and extending outwardly from the side of the bottom for attaching ends of a handle used to lift and carry the container; and, locking means for stacking the container with a similarly formed container so the containers are securely attached to each other to facilitate their movement, the locking means including at least one locking lug extending below one of the ears and a notch aligned with the lug on one container fitting in a notch on a corresponding container with which the stackable container is stacked.
 2. The container of claim 1 in which a circumferential lip is formed about the top of the container and the locking means includes at least one notch formed in the lip.
 3. The container of claim 2 in which the lug extends outwardly from the container sidewall, is vertically aligned with the notch, and is sized to fit into the notch when two containers are stacked together to attach the containers to each other.
 4. The container of claim 3 in which the locking means includes a pair of notches and a pair of lugs, the notches and lugs being oppositely formed on the container with a lug and vertically aligned with each other.
 5. The container of claim 4 in which each notch depends beneath one of the ears.
 6. The container of claim 5 further including a flange extending circumferentially about the container, below the top of the container, and the lug depends beneath the flange for the lug of the container to be received in the notch in the lip of the container with which the container is stacked.
 7. The container of claim 6 further including a second flange extending circumferentially about the container, below the top of the container and above the first said flange, the ears formed on the sides of the container extending between the respective flanges.
 8. The container of claim 1 in which the lug and notch are offset from the ears and not aligned therewith.
 9. The container of claim 8 further including a pair of notches and a pair of lugs being oppositely formed on the container and offset from the respective container ears.
 10. The container of claim 1 in which respective lugs and notches are vertically aligned with each other.
 11. The container of claim 6 in which the body sidewall tapers from the top to the bottom of the container.
 12. The container of claim 1 which is a molded plastic container.
 13. The container of claim 1 in which the handle is a removable handle the ends of which fit in openings in the respective ears. 